Multiple output blowers for dryers and the like



Dec; R966 R. 3. LOUGH ETAL. 3,289,317

MULTIPLE OUTPUT BLOWERS FOR DRYERS AND THE LIKE Filed May 14 1.964 2 Sheets-Sheet 1 MULTIPLE OUTPUT BLOWERS FOR DRYERS AND THE LIKE Filed May 14, 1964 Dec fi, 1966 R. c. LOUGH ETAL.

2 Sheets-Sheet 2 INVENTOR5 fazca ya/z/C. 0J4g/Z fa'z al (9/1 ATTORNEYS United States PatentO 3,289,317 MULTIPLE OUTPUT BLOWERS FOR DRYERS AND THE LIKE Richard C. Lough, St. Joseph, and Carrol A. Orr, Stevensville, Mich, assignors to Whirlpool Corporation, Benton Harbor, Mich, a corporation of Delaware Filed May 14, 1964, Ser. No. 367,317 16 Claims. (Cl. 34-133) This invention relates generally to improvements in blowers and more particularly concerns a new and improved multiple output blower system which is especially suitable for affording selective rates of air flow through laundry type dryers, and the like.

In a drying system of a laundry appliance or dry cleaning machine, it is desirable to drive or circulate a stream of temperature-conditioned air through the treatment zone such as a rotary drum of the machine. While various devices and controls have been proposed for varying the volume of air flowing through the treatment zone, the prio arrangements have been generally characterized by rather complex structures or intricate electrical hook-ups, and the like, which have been costly, unduly subject to servicing liabilities, and often unduly limited in performance.

Accordingly, it is an important object of the present invention to provide new and improved means for adjusting the flow volume of conditioning air through a treatment zone.

Another object of the invention is to provide a new and improved multiple flow characteristic blower construction.

A further object of the invention is to provide a novel blower having three different selective air volume capabilities.

Still another object of the invention is to provide a multiple selective volume blower arrangement motivated through a common shaft.

A still further object of the invention is to provide a two wheel blower assembly operating on a common drive shaft and provided with novel means for selectively varying the volumetric capacity of the assembly.

Other objects, features and advantages of the present invention will be readily apparent from the following de tailed description of certain preferred embodiments thereof taken in conjunction with the accompanying drawings, in which:

FIGURE 1 is a schematic rear elevational view of a laundry dryer incorporating features of the invention;

FIGURE 2 is a circuit diagram illustrating a control circuit especially adapted for the dryer of FIGURE 1;

FIGURE 3 is an enlarged fragmentary vertical sectional detail view taken substantially on the line IIIIII of FIGURE 1; and

FIGURE 4 is a view similar to FIGURE 3 but showing a modification.

As shown on the drawings:

A laundry dryer 5 representative of apparatus with which the present invention has particular utility includes a casing 7 having on its upper portion a console panel 8 and a so-called control tower 9.

In FIGURE 1, the machine is shown with a back wall panel of the casing removed whereby to expose the opcrating components of the dryer apparatus including a dryer drum 10 mounted rotatably on a shaft 11 extending forwardly from a hub 12 of a bulkhead 13 and with reinforcing ribs 14 in the bulkhead radiating from the hub. Rotation of the drum is effected through means such as a drive belt 15 trained over the outer periphery of the drum and over a suitable pulley on the drive shaft of an electric single speed motor 17 of suitable character and speed for the purpose.

3,289,317 Patented Dec. 6, 1966 In addition to driving the drum 10, the single speed motor 17 provides motive power for a blower 18 in an air system by which the interior of the drum is ventilated. For this purpose, the blower has a housing 19 having an exhaust outlet 20 which may be connected to a suitable pipe if the machine is vented to the outside atmosphere or else the discharging air may vent directly into the space in which the dryer is located. Communicating with the inlet of the blower housing 19 is an exhaust duct 21 leading from a large exhaust port 22 extending through the bulkhead 13 into the dryer chamber.

Although the dryer 5' is of the type which could advantageously employ gas burning means as a source of heat, in the present instance it is of the type employing electrical resistance heating in a tempering conduit 23 comprising a thermal energy air stream path mounted on the back of the bulkhead 13 and having a lower air inlet 24 and a temperature-conditioned air outlet 27 communicating through the bulkhead with the drum chamber. Within the conduit 23 are mounted suitable heating elements 28 and 29 (FIG. 2) which may comprise about 3600 watts and 2000 watts capacity, respectively. These are in a control circuit including a three-wire source including lines L L and neutral line N.

In the control circuit is the motor 17, a door operated switch 30 and an indicator light 31. A temperature selector switch 32 includes a movable selector element 33 movable between positions including an air contact position' 34, a low or delicate temperature contact position 35, and a high or normal temperature contact position 37.

In line with the low temperature contact 35 is an operating thermostat 38 In line with the high temperature contact 37 is an operating thermostat 39. The operating thermostats 37 and 38 are located on the exhaust duct housing 21 and are sensitive to the exhaust air as it leaves the treat ment area of the drum 10. These thermostats can be set fordifferent temperatures as desired or required in processing different types of fabrics, or otherwise. A safety thermostat 40 located on the tempering conduit 23 is also provided in the circuit to protect the apparatus against 44 is journalled for rotation in the tower 9 and actuates a switch assembly 46 including selector elements 46a and 46b to control heat input by selective settings of the shaft 44 through the knob 45.

Means are provided for correlating the rate and volume of tempering air flow through the dryer system with the selected heat output of the heat source, this being effected by matching the air translation output of the blower 18 with the heat input to the dryer. Such correlation is effected through the manually operated shaft 44 of the control mechanism by means conveniently comprising a control lever arm 47 extending fixedly radially from the shaft 44 and connected to a suitable remote control actuating device comprising in a simple, direct mechanical arrangement a Bowden wire 48 connected to the outer or free end portion of the rocker or lever arm 47 and guided in a tubular Bowden cable 49 which has its end portion remote from the control arm 47 attached in suitable manner as by means of a clip or brackets 50 to a suitable location on the blower casing or housing 19 and the back of the console panel 8.

According to the present invention, the blower 18 is so constructed and arranged that it will normally operate with maximum output, consonant with the customary normal setting of the heater control circuit for maximum heat input. However, to accommodate additional settings of the heater circuit for lower rate heat input means are provided for controlling functioning of the blower assembly accordingly. In an efficient, simple, effective, compact construction, this is accomplished by the provision of a compound or multiple blower wheel or impeller arrangement within the housing 19, comprising a first or main impeller 51 and in coaxial alignment therewith a second or booster impeller 52. Mounting of the blower wheels or impellers 51 and 52 is in coaxial alignment with an inlet suction port 53 leading from the exhaust end of the air circulation duct 21, with the impeller 51 of predetermined air moving suction capacity and located nearest the port and with the booster impeller 52 in tandem relation thereto between the back of the impeller 51 and the opposite wall of the housing 19.

Means are provided for driving the first impeller 51 continuously during operation of the machine, desirably through power derived from the motor 17. While such power may be transmitted through a suitable transmission, an effective, uncomplicated arrangement comprises coupling the impeller 51 for direct driving by an extension 54 of or on the motor drive shaft. For this purpose, a coupling hub 55 is coaxially mounted on the end portion of the shaft 54, preferably in a detachably fixed relation as by means of a keying set screw 57, and extending through an opening in the adjacent wall of the blower housing. Removable but corotative attachment of the impeller 51 to the hub is effected by means of a coaxial reduced diameter threaded stud 58 on the free terminal end portion of the hub threadedly engaging in a tapped blind end bore 59 in a central hub 60 of the first impeller.

To provide for selectively variable volumetric output for the blower assembly, mounting of the second or booster impeller 52 on the hub 55 is effected to have the booster impeller travel corotatively with the mounting hub or to permit rotation of the mounting hub relative to the booster impeller. To this end, the impeller 52 has a hub 61 which is mounted on a bearing 62 engaging about the mounting hub 55 and enabling relative rotation of the mounting and booster impeller hubs.

Releasable clutch means adapted to be operated by the Bowden wire 48 are provided for coupling the booster impeller 52 through its hub 61 with the mounting hub 55. Accordingly, a clutch sleeve 63 is coaxially positioned for relative movement upon the impeller hub 61 in limited spaced relation about an annular clutch land surface 64 on the mounting hub of substantially equal diameter to an aligned annular clutch land surface 65 on the impeller hub 61. Housed within the clutch sleeve 63 is a coiled spring clutch 67 of well-known type normally clutchingly gripping the aligned clutch land surfaces 64 and 65 and having a terminal 68 anchored to the clutch housing sleeve 63. Since the clutch spring normally contracts into common gripping engagement with both of the contiguous, aligned clutch surfaces 64 and 65 it normally couples the booster impeller 52 to corotate With the mounting hub 55 and thus with the main impeller 51 to afford maximum air circulation rate and volume through the dryer system.

The maximum air volume flow is obtained when control arm 47 is in the high position as shown in FIG- URE 2. When maximum air flow is selected, the switch contacts 46a and 46b are in the position as shown by the solid lines, thus causing maximum heat input and the energization of the indicator light 31.

When it is desired to disconnect the booster impeller 52 and hold it against operation so that only the main impeller 51 will be effective for moving air through the dryer, the Bowden wire 48 is operated to function as a stop (as shown by the dotted line in FIGURE 3) by driving it into clutching engagement with any one of a plurality of sockets or stop shoulders afforded by radially outward clutch teeth 69 provided integrally on the outer perimeter of the clutch housing sleeve 63 and by the applying of a braking force on hub 61 by the brake material fixed to the end ofthe Bowden wire projection 48a. By thus stopping the clutch sleeve 63 and thereby the impeller 52, the anchored terminal 68 of the clutch spring 67 is caused to effect a torque uncoupling of the spring from the mounting hub clutch surface 64. This enables the mounting hub 55 to run free in bearing 62 relative to the now stationary booster impeller 52. It will be understood that by such declutching of the booster impeller 52 relative to the main impeller 51 the stationary position of impeller 52 is effected by the manipulative movement of the control mechanism control arm 47 to the lowest heat input control position thereof as shown in the low position in FIGURE 2 with the switch arms 46a and 46b in the dotted line position.

In addition to the high volume output and the low volume output relationships of the dual impeller blower 18, a third, intermediate volume relationship is attainable by virtue of a generally free wheeling relationship of the booster impeller 52 relative to the main impeller 51. This relationshsi is attained by positioning the Bowden wire 48 in an intermediate position so that braking force is not applied by the brake surface 85 against hub 61, but the clutch teeth '69 of clutch housing sleeve 63 are engaged by Bowden wire 48. Due to friction between the bearing 62 and the hub 61 and the induced force of the air on the booster impeller 52 from main impeller 51, the booster impeller will free wheel at a speed somewhat lower than the driven speed of main impeller 51. As a result of the torque lag and underrunning speed of the booster impeller 52, there is a reduction in the pressure drop from the main impeller 51 to the booster impeller 52 and thus a reduction in the total pressure and volume at the discharge outlet 20 of the blower, as compared to the condition prevailing when both of the impellers are coupled for joint, common speed rotation. Full joint rotation of the dual impellers can be resumed by the complete withdrawal of the Bowden wire 48 from engagement with the clutch teeth 69.

In the modified arrangement of FIGURE 4, the same results are attained, namely, the pulling of selective multiple volumes of air through the dryer although the blower operates on a single shaft Which may be operated at a single speed or at variable speeds in any selected speed of which selective multiple volumes of air are attainable. In this modified blower arrangement 18' there is included the main first blower or impeller wheel 51' and the second or booster blower or impeller wheel 52' mounted to be driven through a shaft 54 to which is corotatably concentrically coupled a mounting hub 55' secured as by means of a retaining stud 57 which retains the main impeller wheel 51 to rotate fixedly with the hub 55 by means of a threaded stud extension on the free terminal of the hub secured into a coaxial socket 59 in the hub 60 of the main impeller wheel. Through a hub 61 the booster impeller wheel 52 is mounted on the mounting hub 51' which carries a bearing 62 for this purpose. In this instance, a clutch member 63 in the form of a bushing is mounted fixedly within the hub 61 although if preferred it may comprise an integral part of the hub 61'. On its inner end the clutch bushing 63 has a radial flange 70 spaced suitably from the adjacent end of the hub 61 and providing a groove 71 within which is engaged a clutch actuator yoke 72 connected to one end of a bell crank 73 pivotally secured at its elbow as by means of a bracket 74 to the outer side of the blower housing wall 19'. Adjacent to its opposite end the bell crank is attached to the Bowden wire 48' which is guided in the Bowden cable 49 and attached to the blower housing by the bracket 50'. Operation of the Bowden wire 48' in substantially the same manner as the Bowden wire 48 of FIGURES 1 and 3 correlates operation of the blower 118 with heat input as regulated by the control mechanism and circuitry of the machine.

In the embodiment of FIGURE 4, the arrangement is such that when the Bowden wire 48 is driven in one direction, in this instance to rock the bell crank lever 73 to move the clutch bushing 63' and thereby the hub 61' axially on the bearing 62 to move the booster impeller 52 toward the wall of the housing 19', that is outwardly toward the right as seen in FIGURE 4, the booster impeller is clutched to remainstationary or at rest. In a convenient and desirable arrangement, an annular oblique clutch surface 75 on the hub 61' opposes and engages a friction clutch brake surface 77 in the form of a band of brake material secured fixedly to an opening-defining flange 78 on the blower casing complementary to the clutch surface 75. Thus, when the Bowden wire 48' is drawn upwardly it causes the clutch actuator bell crank 73 to push against the clutch bushing flange 70 to shift the booster impeller 52 axially and thrust the clutch surface 75 against the brake liner friction clutch 77 and immobilize the booster impeller.

When the blower wheel control Bowden wire member 48 is released completely (shown as the high setting of control arm 47 in FIGURE 2), during powered driving of the main impeller 51', the vacuum created by impeller action of the main impeller wheel 51 draws the booster impeller wheel 52' axially toward the main wheel where by an annular oblique clutch surface 79 on the hub 61 locks into an annular friction clutch brake lining 80 fixedly mounted on a complementary flange surface 81 provided on the adjacent end of the impeller hub 60' (as shown in the dotted line position in FIGURE 4). Thereby, the booster impeller 52 is caused to rotate with the main impeller 51' and augment the air flow through the blower to the maximum capacity at the driving speed.

When it is desired to effect an intermediate air flow between maximum and minimum, the arrangement is such that the booster impeller 52 is permitted to free wheel to substantially the same effect as the booster impeller 52. This is effected by an intermediate setting (shown as the med. setting of control arm 47 in FIGURE 2) of the control clutch lever 73 wherein neither of the clutch surfaces 75 or 79 engages its opposing friction clutch band or liner, but system friction and mechanical as well as air drag cause the booster impeller 52 to rotate in an underrunning relation to the main impeller 51.

The simultaneous control of the heat input with the control of the volume air flow in the embodiment of FIGURE 4 is as described above for the embodiment of FIGURE 3. The control arm 47 position determines the air flow rate and the heat input.

While the drive shaft 54' may be directly coupled to or be an extension of the motor drive shaft of the drive motor of the machine, it may be an idler stub shaft with motivation of the impellers of the blower through a flexible drive coupled to the hub 55 such as a suitable drive belt (not shown) trained over a pulley extension 82 on the hub 55. It will be understood that this same driving arrangement may be utilized in respect to the impellers of the blower 18 of FIGURE 3.

Both forms of the invention, it will be apparent, provide a novel selective multi-stage blower construction which, in the illustrated examples, is adapted to afford three different air volume stages for any given driving speed of the drive shaft. Where the drive shaft is capable of various selected speeds, a large number of variables in output volume of the blower are attainable through the clutch controlled functional orientations of the booster blower wheel impeller and the continuously driven main blower wheel impeller.

Although minor modifications might be suggested by those versed in the art, it should be understood that we WiSh to embody within the scope of the patent warranted hereon all such modifications as reasonably and properly come within the scope of our contribution to the art.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as fol- 5 lows:

1. A dryer comprising means providing a treatment zone in which materials are to be treated and power driving means,

means defining an air circulation path, having thermal energy means therein,

means for controlling operation of said thermal energy means to vary the thermal energy input into an air stream in said path,

a blower assembly for generating said air stream in said path and comprising a housing and a plurality of coaxially mounted cooperatively and relatively operable impeller wheels therein and having driving connection with said driving means, and means for controlling operation of said impeller wheels for selectively varying the output volume of the blower in accordance with input variations of said thermal energy means.

2. A dryer as defined in claim 1, in which said means for controlling operation of said impeller wheels comprise clutch structure and means for correlating operation of the clutch structure with said means for controlling operation of the thermal energy means.

3. A dryer as defined in claim 2, in which the means for controlling operation of the thermal energy means and the means for controlling operation of the clutch structure have a common manual actuator.

4. A dryer as defined in claim 1, in which the means for controlling operation of the thermal energy means and the means for controlling operation of the impeller wheels include a common manual operating shaft provided with a mechanical operating connection with the impeller wheels.

5. A dryer as defined in claim 1, wherein said impeller wheels have three relative adjustments affording three stages of volume output for a given driving speed of the driving means.

6. A dryer comprising means providing a treatment zone in which materials are to be treated and power driving means,

means defining an air circulation path,

a blower assembly for generating an air stream in said path and including a shaft driven by said driving means,

a pair of impeller wheels mounted on said shaft,

one of said impeller wheels being fixed on the shaft and the other of the impeller wheels being adapted for relative rotation of the shaft with respect thereto,

and means for selectively coupling and uncoupling said other of said impeller Wheels with respect to said shaft and the impeller wheel fixed on the shaft.

7. A dryer comprising means providing a treatment zone in which materials are to be treated and power drivmg means,

60 means defining an air circulation path,

a blower assembly for generating an air stream in said path and including a shaft driven by said driving means, a pair of impeller wheels mounted on said shaft,

one of said impeller wheels being fixed on the shaft and the other of the impeller wheels being adapted for relative rotation of the shaft with respect thereto,

and releasable clutch means for selectively coupling the other of said impeller wheels with the shaft.

8. A dryer comprising means providing a treatment Z0116 in which materials are to be dryed and power drivmg means,

means defining an air circulation path having thermal energy means therein,

means for controlling operation of said thermal energy a booster impeller relatively rotatably mounted on said hub,

' first clutch means for retaining said booster impeller against rotation with said hub,

means operated synchronously with said thermal energy controlling means for operating said first clutch means,

and second clutch means operative for selectively coupling the booster impeller for rotation with said rotary structure.

mounted thereon,

a booster impeller relatively rotatably mounted on the mounting hub,

and clutch means selectively operative for effecting corotation of the booster impeller and the hub in one stage or to retain the booster impeller non-rotative wit-h respect to the hub in a second stage or to effect a corotative but underrunning relation of the booster impeller relative to the hub in a third stage.

11. A blower as defined in claim 10, in which the clutch means comprise a clutch member rigid with the booster impeller and a torsion spring clutch coupled therewith and having engagement with a clutch surface on the hub.

12. A blower as defined in claim 10, wherein said clutoh means comprise respective clutch surfaces on the booster impeller and on a stationary portion of the blower.

13. A blower construction adapted for generating an air stream in a laundry dryer and including,

a housing having an inlet opening and an outlet,

a main impeller aligned with said inlet opening to draw air therethrough and drive the air from said outlet, hub mounting said main impeller corotatively and having means for coupling with a single speed drive means,

booster impeller having a hub rotatively mounted on said mounting hub,

clutch sleeve mounted coaxially with the booster impeller hub and disposed in limited spaced encompassing relation to aligned cylindrical clutch surfaces of common diameter on said booster impeller hub and on said mounting hub,

spring clutch wrapped about said clutch surfaces and anchored at one end to said sleeve and said spring clutch providing a corotational connection of said mounting :hub and said booster hub,

said sleeve having on its radially outer surface means providing clutch stop shoulders,

clutch stop means mounted on said housing and sesaid mounting hub and booster hub when said clutch sleeve is stopped from rotation by said stop means and thereby releasing said corotational connection,

and brake means operatively connected to said clutch stop means to provide a braking and holding force to said booster hub to prevent rotation of said booster hub when said clutch stop means is actuated.

14. A blower construction adapted for generating a variable volume air stream through a laundry dryer 10 including,

a housing having inlet and outlet openings,

a main impeller in the housing aligned with the inlet opening to draw air therethrough and drive it from the outlet opening,

a mounting hub corotatively mounting the main impeller and :having means for coupling to a power source to drive the hub and main impeller at predetermined speed,

a booster impeller having a hub structure rotatably mounting it on said mounting hub within the housa clutch actuator mounted on the housing andopertive for selectively axially moving the booster impeller and its hub on the mounting hub,

an annular clutch surface on the booster impeller hub facing a complementary friction clutch surface on the main impeller and operative to effect corotation of the booster impeller with the main impeller for maximum volume air movement through the blower housing,

an annular clutch surface on the opposite end portion of the booster impeller hub,

and friction clutch surface means on the housing opposing said last mentioned clutch surface and being adapted to be engaged thereby when said actuating means is operated to shift the booster impeller hub in that direction.

15. A blower as defined in claim 14, wherein said actuv ator is operative to maintain the booster impeller hub and thereby the booster impeller in an intermediate position between said friction clutch surfaces and in which the booster impeller turns with but underruns said mounting hub and said main impeller.

16. A blower construction adapted for generating an air stream through a clothes dryer, comprising:

a housing,

a plurality of impellers mounted in said housing,

and means operative to control functioning of said impellers to afford three stages of air volume in the stream generated by the blower and including one stage in which the impellers rotate at a common speed, a second stage in which one impeller operates at continuous speed and a companion impeller is held stationary, and a third stage in which one of the impellers operates at continuous speed and a companion impeller rotates at a reduced speed.

References Cited by the Examiner UNITED STATES PATENTS 2,203,843 6/1940 Pierce 230131 3,208,389 9/ 1965 Stefan 10398 FOREIGN PATENTS 13,206 1911 Great Britain.

FREDERICK LQMATTESON, JR., Primary Examiner.

JOHN J. CAMBY, Examiner, 

7. A DRYER COMPRISING MEANS PROVIDING A TREATMENT ZONE IN WHICH MATERIALS ARE TO BE TREATED AND POWER DRIVING MEANS, MEANS DEFINING AN AIR CIRCULATION PATH, A BLOWER ASSEMBLY FOR GENERATING AN AIR STREAM IN SAID PATH AND INCLUDING A SHAFT DRIVEN BY SAID DRIVING MEANS, A PAIR OF IMPELLER WHEELS MOUNTED ON SAID SHAFT, ONE OF SAID IMPELLER WHEELS BEING FIXED ON THE SHAFT AND THE OTHER OF THE IMPELLER WHEELS BEING ADAPTED FOR RELATIVE ROTATION OF THE SHAFT WITH RESPECT THERETO, 